1. Technical Field
The present disclosure relates to negative pressure wound therapy systems and, more particularly, to a fluid collection canister including a canister top with a filter membrane and negative pressure wound therapy systems including the same.
2. Discussion of Related Art
Negative pressure therapy, also known as suction or vacuum therapy, has been used in treating and healing wounds. Treating an open wound by applying negative pressure, e.g., reduced or sub-atmospheric pressure, to a localized reservoir over a wound has been found to assist in closing the wound by increasing blood circulation at the wound area, stimulating the formation of granulation tissue and promoting the migration of healthy tissue over the wound. Negative pressure therapy may also inhibit bacterial growth by drawing wound fluids from the wound such as exudate, which may tend to harbor bacteria. Negative pressure therapy can thus be applied as a healing modality for its antiseptic and tissue regeneration effects. This technique has proven effective for treating a variety of wound conditions, including chronic or healing-resistant wounds and ulcers, and is also used for other purposes such as post-operative wound care.
Generally, negative pressure therapy provides for a wound covering to be positioned over the wound to facilitate suction at the wound area. A conduit is introduced through the wound covering to provide fluid communication to an external vacuum source, such as a hospital vacuum system or a portable vacuum pump. Atmospheric gas, wound exudate or other fluids may thus be drawn from the reservoir through the fluid conduit to stimulate healing of the wound. Generally, a fluid collection canister for collecting fluids aspirated from the wound is positioned in the suction line between the wound covering and the vacuum source. Exudate drawn from the reservoir through the fluid conduit may thus be deposited into the collection canister.
During a treatment, vacuum levels within a negative pressure wound therapy system may be monitored and controlled. There are a variety of pressure detecting devices such as pressure gages, switches, transducers and transmitters that can be used for measuring vacuum levels. A negative pressure wound therapy system may not function properly when fluid contamination of various components degrades the capability to accurately measure vacuum levels in the negative pressure wound therapy system. When the collection canister is tilted from upright, fluid may occlude a filter in communication with a pressure detecting device, preventing accurate measurement of vacuum levels in the negative pressure wound therapy system. This may cause the negative pressure wound therapy system to react as if a pneumatic leak is present in the system and may cause vacuum level within the collection canister to go uncontrolled, which may result in improper therapy to the patient.
A mechanism for preventing overfilling of the collection canister may prevent fluid contamination of various components of the negative pressure wound therapy system and help to prevent spillage or leakage of exudate. During a treatment, the collection canister may be prevented from overfilling by a hydrophobic filter at the top of the collection canister that shuts off the air flow to the vacuum source when the collection canister is full. In portable negative pressure wound therapy systems, which may be worn or carried by a patient, there is a likelihood that the apparatus will shift into various orientations while the patient is ambulating, allowing exudate to occlude the filter when the collection canister is not full. Negative pressure therapy may be discontinued or interrupted inadvertently when the filter is occluded during patient ambulation or when the collection canister is tipped over. There is a need for a negative pressure wound therapy system that permits accurate measurement of vacuum levels in the negative pressure wound therapy system and is capable of providing negative pressure therapy for varied orientations of the collection canister.